Hexagonal phalanx?

[causative]

Formations are usually depicted as a square grid, each soldier directly behind the soldier in front of him.  But circles and probably soldiers can be packed more densely in a hexagonal grid, with each row of soldiers offset 50% from the row in front of it.  This would also enable the second row from the front to see ahead more clearly, since their vision wouldn't be blocked by the heads of soldiers in the front row, which would help the second row to stab at the enemy.  (Of course, the overall formation can still be rectangular even though the rows are offset hexagonally.)  Is there any clear primary evidence against this notion?

Edited June 29, 2017 by causative

[wowgetoffyourcellphone]

7 hours ago, causative said:

 Is there any clear primary evidence against this notion?

I don't think there's any for it either though.